As the improvement in the field of optoelectronic, the volume of optoelectronic devices are getting smaller by using techniques of micro-display. Because of the breakthrough of the manufacturing size of the light emitting diode (LED), the display made of micro-LED array draws highly attention in the business market. Displays made of micro-LEDs belong to active light emitting device displays. Micro-LEDs have similar contrast and energy consumption comparing to organic light emitting diodes, but much superior in reliability and life-time. Therefore, micro-LEDs have a great potential to be adapted to communication devices, internet of things, and displays of wearable electronics.
A display of micro-LEDs is made of LED arrays disposing on an electronic substrate, to form the pixels of the display. In the manufacturing process of the micro-LED display, the LEDs must be respectively arranged on the pre-determined position of contacts on the substrate. Therefore, alignment and packaging become important issues in manufacturing display of micro-LEDs.